Left to right
On paper we add the ones first. On the abacus we always start with the highest place. This feels strange at first, but it is faster and lets you read the answer as you go.
Without carrying
Example: 34 + 25. Set 34. Add 2 on the tens rod (→ 54). Add 5 on the ones rod (→ 59).
With carrying
Example: 47 + 36.
- Set 47.
- Tens: add 3 to the 4 → 77.
- Ones: add 6 to the 7. The rod cannot hold 13, so use a big friend: take away 4 from the ones rod and add 1 on the tens rod → 83.
The friends work on every rod. Adding 6 tens to 7 tens uses exactly the same moves as adding 6 to 7 – just one rod further left.
Try it yourself
Show 47, then add 36: tens first, then ones.
Your abacus shows 0.
Quick check
Type your answers, then check them. Get them all right to complete the lesson automatically.
Practice tips
- Before each move, ask: can I add directly? If not, small friend? If not, big friend?
- Practise adding the same number repeatedly (e.g. +27 five times) to build rhythm.